"The friction coefficient is not the percent of force which is resisted, it's the ratio between the force between object/ground and friction."

But that's what Jason Rox said: " 50% of it's total vertical force?"

Essentially, yes, in order to keep something moving at a constant speed on a horizontal surface, you must apply a force equal to the friction force which is the friction coefficient times the "total vertical force".

Friction exists because surfaces are uneven if you look REALLY close. You see little bumps, which the object must overcome to slide across the surface.

So if the surface consisted of walls, like a maze, it would be quite difficult to slip a television through without going around the walls. In the end, the bigger the bumps, chances are the coeficient of friction is higher.